CA1074044A - Spray-dried phenolic adhesives - Google Patents
Spray-dried phenolic adhesivesInfo
- Publication number
- CA1074044A CA1074044A CA259,975A CA259975A CA1074044A CA 1074044 A CA1074044 A CA 1074044A CA 259975 A CA259975 A CA 259975A CA 1074044 A CA1074044 A CA 1074044A
- Authority
- CA
- Canada
- Prior art keywords
- phenol
- formaldehyde
- resin
- process according
- formaldehyde resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/12—Powdering or granulating
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
- C08G8/04—Condensation polymers of aldehydes or ketones with phenols only of aldehydes
- C08G8/08—Condensation polymers of aldehydes or ketones with phenols only of aldehydes of formaldehyde, e.g. of formaldehyde formed in situ
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
- C08G8/28—Chemically modified polycondensates
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
- C08G8/38—Block or graft polymers prepared by polycondensation of aldehydes or ketones onto macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
- C08L61/04—Condensation polymers of aldehydes or ketones with phenols only
- C08L61/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
- C08L71/02—Polyalkylene oxides
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2361/00—Characterised by the use of condensation polymers of aldehydes or ketones; Derivatives of such polymers
- C08J2361/04—Condensation polymers of aldehydes or ketones with phenols only
- C08J2361/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols
- C08J2361/14—Modified phenol-aldehyde condensates
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L3/00—Compositions of starch, amylose or amylopectin or of their derivatives or degradation products
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L97/00—Compositions of lignin-containing materials
Abstract
Abstract of the Disclosure A method of preparing a modified phenol-formaldehyde resin in solid particulate form comprising reacting together, in an aqueous medium, phenol and formaldehyde, in a ratio of 1.0 mole phenol to between 1.8 and 3.5 moles of formaldehyde, in the presence of between 0.1 and 1.0 moles of a basic catalyst; continuing this reaction until a desired viscosity is reached;
modifying the reaction system by adding thereto between 0% and 30%, based on the weight of phenol originally taken of a non-phenolic polyhydroxy compound;
spray drying the thus modified liquid resin in a pressure nozzle drier, and chilling the spray dried particulate solid. These solid resins are redisper-sible in water and stable on storage, compared to the known aqueous, equivalent, systems.
modifying the reaction system by adding thereto between 0% and 30%, based on the weight of phenol originally taken of a non-phenolic polyhydroxy compound;
spray drying the thus modified liquid resin in a pressure nozzle drier, and chilling the spray dried particulate solid. These solid resins are redisper-sible in water and stable on storage, compared to the known aqueous, equivalent, systems.
Description
1074049, Base-catalysed phenolic adhesives are usually prepared in a liquid form, the most common solvent being water. The solubility and dilutability of the product are determined by several factors, the most important being the catalyst used, the phenol to aldehyde molar ratio used, and the amount of catalyst used. But this basic reaction whereby the resin is prepared, although carried out at an elevated temperature, generally 50C to 100C, never stops, and continues in the solution on storage, albeit at a slow rate.
This lack of stability severely limits product usefulness, as dilutability and viscosity are adversely affected by storage. As a consequence, these aqueous systems have to be prepared close to where they are to be used, and ideally are prepared and used at the same rate, with minimal storage times.
Also, where some transportation cannot be avoided, since the system contains of the order of 50% water, transportation is costly, particularly in compari-son with the known solid resins. Further, the high water content of liquid resins is undesirable in applications where prolonged heat application to effect its removal is required. In addition to the cost, such prolonged heating can adversely affect the material being bonded, with detriment to the properties of the product.
We have now found that a range of phenol-aldehyde resins, hitherto known only as aqueous solutions or dispersions, can be obtained as a parti-culate solid by spray-drying such an aqueous suspension or solution. We have further found that the capability of such resin solutions or dispersions being processable to a particulate solid by spray drying is markedly enhanced by the incorporation therein of a non-phenolic polyhydroxy compound.
Thus in one embodiment this invention provides a method of preparing a phenol-formaldehyde resin in solid particulate form comprising reacting together, in an aqueous medium, phenol and formaldehyde, in a ratio of 1.0 mole phenol to between 1.8 and 3.5 moles of formaldehyde, in the presence of between 0.1 and 1.0 mole of a basic catalyst; continuing this reaction until a desired viscosity is reached; spray drying the solution or dispersion of -1- ~ ., phenol-formaldehyde resin thus produced in a pressure nozzle drier; and chilling the spray dried particulate solid so produced for storage.
In a preferred embodiment this invention provides a method of pre-paring a phenol-formaldehyde resin in solid particulate form comprising reac-ting together, in an aqueous medium, phenol and formaldehyde, in a ratio of 1.0 mole of phenol to between 1.8 and 3.5 moles of formaldehyde in the pre-sence of between 0.1 and 1.0 moles of a basic catalyst; continuing this reaction until a desired viscosity is reached; modifying the reaction system by adding thereto between 0 and 30%, based on the weight of the phenol origin-ally taken, of a non-phenolic polyhydroxy compound; spray drying the thus modified liquid resin in a pressure nozzle drier; and chilling the spray dried particulate solid for storage.
In an alternative process according to this embodiment of the inven-tion, the non-phenolic polyhydroxy compound is incorporated at up to 30% by weight of phenol into the initial reaction mixture.
Insofar as the conditions of reaction, and reactants used in pre-paring the phenol-formaldehyde resin are concerned, standard conditions, proce-dures, and reactants well known in the art are used.
The term "phenol" can include not only pure and technical grade phenol, but also cresols with a high meta- and para-cresol content. The preferred phenol composition is one with a boiling range of 180 -200C, con-taining not more than 15% by weight of ortho-cresol plus xylenols.
The formaldehyde, can be used in any of the commercially available forms containing from 37% to 100% aldehyde, such as aqueous solutions, para-formaldehyde, etc. An aqueous solution of formaldehyde is preferred.
The basic catalyst can be an alkali hydroxide, or carbonate, or an alkaline earth oxide or hydroxide. The preferred catalyst is sodium hydroxide, but barium hydroxide, calcium hydroxide and calcium oxide all produce usable resins.
~074044 The non-phenolic polyhydroxy compound can be chosen from glycols, such as ethylene glycol, propylene glycol, butylene glycol, and diethylene glycol; polyhydroxy ethers, such as the Voranols*, and other polymeric hydroxy materials, for example the Carbowaxes*; and polyhydroxy compounds such as glycerol, sorbitol, cane sugar, etc. It is also contemplated that mixtures of polyhydroxy compounds can also be used.
To obtain a useful adhesive resin suitable for spray drying, the molar ratios of phenol, formaldehyde, and catalyst have to be controlled and kept within the following limits: phenol, 1.0 mole; formaldehyde, 1.8 to 3.5 moles; catalyst, 0.1 to 1.0 moles. The amount of polyhydroxy compound also should not exceed 30% by weight of the weight of phenol taken.
In an alternative embodiment, this invention provides a spray-dried particulate solid phenol-formaldehyde resin, containing up to 30% by weight of the phenol present of a polyhydroxy compound.
Preferably the spray drying step is carried out on the liquid resin dissolved or dispersed in water using a pressure nozzle drier. It is desir-able to chill the spray dried particles quickly to below 20C for storage.
The nature of the product can be further modified for use by the introduction of other materials, such as dyes; extenders and fillers; plasti-cisers; anti-static agents; release agents; and so forth.
The spray dried phenolic adhesives of this invention have a number of advantages, especially where systems which it has not hitherto been poss-ible to convert into solid form are concerned. The spray dried material is an easily handled, free flowing powder, which can be used as such, or, where relevant reconstituted to a liquid system by the addition of the desired amount of water. Particular advantages obtained by use of these solids are:
(a) the solid systems do not suffer from the lack of stabili~y exhibited by liquid systems; they can be stored if kept dry and preferably below about 70 to 75F (21 to 24C) for at least 6 months, as compared to their liquid i * Trade Mark counterparts which have only a limited shelf-life.
(b) wllere relevant, reconstitution to a liquid resin with retention of desirable viscosity and dilutability characteristics.
~c) shorter pressing times and lower pressing temperatures when spray-dried adhesive is used in place of liquid adhesive in manufacture of waferboard, chipboard and the like, thus maintaining short cure cycles and minimising damage to the furnish.
~d) better economics of storage and transportation as the 50% water content of a liquid resin is removed.
~e) better utilization of resin, since the loss of relatively low molecular weight components, which generally are lost in, for example, the white water in board making, is virtually eliminated; this has the consequence that pollution problems associated with white water treatmen* are also alleviated.
~f) improved economics of production involving shorter batch processing -times, and powder production without grinding.
Spray drying is an operation in which a liquid feed is converted to a fine spray, the moisture in the feed evaporated by means of a stream of hot gas (usually air) and the dry powdered product then separated from the gas. The process can be applied to solutions, emulsions or slurries or any material that can be pumped. Moisture evaporation, both free and chemically bound, is controlled by temperature and moisture gradients in the material during drying. The ease of drying of materials depends on the temperature difference between inlet and outlet drying air - the greater permissible difference, the easier the drying.
Spray dried particles are usually spherical; solutions produce hollow beads while slurries produce solid beads. The particle size varies with degree of atomization and percent solids in the feed. Other character-istics of the dried material such as moisture content, flowability, etc. are controlled by operational variables such as droplet size, air flow rate, air temperature and humidity.
Phenol-formaldehyde resins fall into a class of materials that have low softening points. During drying, the tacky particles have to be chilled down below softening point in the layer of cool air and thus be pre-vented from sticking to surfaces. Generally used temperatures for drying phenol-formaldehyde resins are 210 - 180C at the inlet and 90 - 100C at the outlet.
In the Examples, the following test procedures are used to obtain the cited test results.
A. MELT POINT, FLOW AND CURE OF REACTIVE PHENOLICS
Softening Point - Capillary Method A capillary sealed at one end is filled with powdered material to a depth of 2 cm. The tube is attached to a thermometer so that the resin is next to the bulb and the thermometer is immersed in a clear bath heated at 3C/min. The softening point is recorded as the point at which the resin first contracts away from the side of the capillary tube.
Inclined Glass Plate Flow Test A pressed pellet of the resin (0.5 g) is placed at one end of glass plate kept in horizontal position at 125C in convection oven. After 3 min.
preheat time, the plate is tilted 65 from horizontal and testing continued for additional 20 minutes. The glass plate is removed from the oven, cooled and the length of the flow is measured in millimeters and recorded.
Hot Plate Cure Powdered resin (lg) is spread over 2" square area on a hot plate maintained at 150C. Timing is started and the resin is stroked and patted alternately. As the resin advances and becomes more viscous, it will 'string' from spatula during patting. The point in time at which the resin no longer sticks to the spatula and the spatula lifts clear is recorded as the cure time.
1~74~D44 _. MODULUS OF RUPTURE (ASTM D1037) Modulus of rupture (MOR), a static bending test, is carried out us-ing a suitable testing machine (E4) on preconditioned or soaked specimens cut along the two dimensions of the board and measuring 3" x 6" for boards over 1/4" thick. The specimens are subjected to load application at mid span with supports being 4" apart at a uniform rate of load increase.
Modulus of rupture is reported in pounds per square inch calculated from 3 x maximum load x span MOR 2 x width of spec. x (thickness)2 C. INTERNAL BOND (ASTM D1037) Internal bond strength (IB) or tensile strength perpendicular to the surface is determined by testing preconditioned 2" x 2" specimens.
The specimens are bonded to the loading blocks which are engaged in heads of the testing machine. The specimens are subjected to stress to failure with the load passing through the center of the specimens in a continuous fashion at a uniform rate.
Internal bond strength is calculated from the maximum load at fail-ure per square inch. The location of the line of failure is also reportèd.
D. VISCOSITY
Viscosity measured by means of a Gardner-Hold Viscosity Comparator, to stated letter viscosity.
Examples Example 1. RESIN A L
Phenol 1 mole Pormaldehyde (44% Sol.) 2 moles Sodium Hydroxide (50% Sol.) .65 mole Water To make up 45% N.V.
Phenol, formaldehyde, water and 1/3 amount of base required were heated under reflux with agitation to 60 and held at 60C with cooling for .. . . - . - :~
: . ' : -, ' : ,, -, : . ' ~ :, . .
30 minutes. The balance of sodium hydroxide was added and the mixture held at 80C to viscosity D. The resin was cooled rapidly for storage.
Example 2. RESIN A S
The above liquid resin was spray dried at 45~ solids to give a free flowing powder with no flow or cure but infinite solubility in water.
Example 3. HARDBOARD FROM RESINS AL, AS
Resin A S was reconstituted with water to 45% solids and then dilu-ted further to 8% solids. The dilute resin solution was sprayed into a wood furnish slurry buffered at pH 4.5 at 2% resin level. The slurry was drained and the mat pressed at 350F for 6 min. to form hardboard.
Hardboard was also prepared with original liquid resin AL.
Physical testing: AL IB 34 psi AS IB 38 psi Example 4. RESIN B L
Phenol l mole Formaldehyde ~37% Sol.) 2 mole Sodium Hydroxide ~50% Sol.) 0.83 mole l~ater to make up 45% N.V.
Phenol, formaldehyde ~l/2 of requirement) water and sodium hydroxide ~56% of requirement) were heated under reflux with agitation to 100C and held at the temperature until viscosity T was reached. The mixture was cooled to 60C and formaldehyde (balance) was added and the mixture held at 75 until viscosity X was reached. The mixture was cooled to 50C and the balance of sodium hydroxide was added and the resin held at 60C for viscosity 0. The resin was cooled rapidly for storage.
Example 5. RESIN B S
The above liquid resin was spray dried at 45% solids to a free flowing powder with no flow or cure but fully soluble in water.
.. .
1074044 :
Example 6. PLYWOOD FROM RESIN B S
Resin B S was reconstituted with water to 45% solids and formulated into plywood adhesive using the following formulation:
Resin200 parts Water60 parts Norprofil 30 parts Wheat flour 6 parts Soda Ash 6 parts Exterior grade plywood was prepared using the above mix as adhesive at 58 lb/1000 sq. ft. double glueline at 300F, 200 psi for 3/8" thick, 3 ply, at 4.75 mins. press time for two panels per opening. This was compared with the product obtained with original liquid resin as adhesive. The speed of cure was compared for BL and BS resins, using wood failure test as specified by ASTM.
Press time, min.
4.75 5.25 6.25 BL Wood Failure %49 68 74 BS Wood Failure %23 64 98 Example 7. RESIN C L
Phenol 1 mole Propylene Glycol 0.5 mole Formaldehyde ~44% Sol.) 1.9 mole Sodium Hydroxide ~50% Sol.) 0.18 mole Water To make up 45% N.V.
Phenol, propylene glycol, water, formaldehyde ~90% of requirement) and sodium hydroxide ~50% of requirement) was held with agitation at 50C
for 30 minutes. Formaldehyde ~balance of requirement) and sodium hydroxide ~25% of requirement) was added and the mixture heated to 75C and held at that temperature for 30 minutes. Balance of sodium hydroxide was added and the reaction mixture held at 75C for viscosity H. Resin was cooled rapidly for storage.
'' , ,,:, ' : '. . ' -- , . ~ , . . . .
' ' ' ' '~
1~74044 Example ~. RESIN C S 1 The resin C L was spray dried to a find powder which had limited solubility in water and cure of 0-10 sec.
Example 9. RESIN C S 2 The resin CL was treated with propylene glycol (6% approx. on phenol used initially) and spray dried, to a fine powder with cure of 10-30 sec and solubility in water.
Example 10. WAFERBOARD FROM RESIN C S 2 Preparation and Results: 7/16~' Board prepared at 3% resin content.
pressed at 410 F for 4 minutes had IB 44.5 and MOR 3360.
Moulding compound from C S 2 A moulding compound was prepared using the above resin by processing the following mix:
Resin 100 parts Line 2 parts Carbon Black4 parts Calcium Stearate1 part Wood flour106 parts Asbestos 4 parts Furfural 1.5 parts A compound with 50 sec. cure and 8 sec. flow at 150 psi was ; obtained.
Example 11. RESIN D L
Phenol 1 mole Formaldehyde (44% Sol.) 2.2 mole Barium Hydroxide4% on phenol Sodium Hydroxide t50% Sol.) .7 mole Water To make up 45% N.V.
Phenol, formaldehyde, water and barium hydroxide (1/5 of the requirement) were heated to 50 with agitation and held at that temperature _ 9 _ , 107~044 for 30 minutes. More barium hydroxide (2/5 of requirement) was added and the mixture held at 60C for 30 minutes. The balance of barium hydroxide was then added and the mixture held at 80C for 30 minutes. Sodium hydroxide was next added in two portions and the resin held at 90 for viscosity G.
The resin was cooled rapidly for storage.
Example 12. RESIN D S
The above liquid resin was spray dried into a fine powder, possess-ing flow and cure (0-10 sec.) and infinite solubility in water.
Example 13. WAFERBOARD FROM RESIN D S
Preparation and results: 7/16" Boards prepared with 3% solid resin at 400F
for 5 minutes had IB 45.0 and MOR 2615.
Example 14. RESIN E L
Phenol 1 mole Formaldehyde (44% Sol.) 2.2 mole Calcium Oxide 5%
Sodium Hydroxide ~50% Sol.) .42 mole Water to make up 45% N.V.
Example 15. RESIN FS
The above resin was treated with propylene glycol (8% approx. on phenol taken initially) and spray dried to a free flowing powder with flow and cure (25-35 sec.) possessing solubility in water.
Example 16. WAFERBOARD FROM RESIN FS
5/16" Board prepared with the resin (3% powder) at 400F and 4 minutes press had IB 55.5 and MOR 2682.
Ex~mple 17. RESIN G L
Cresol .15 mole Phenol 1.0 mole Propylene Glycol.3 mole Formaldehyde 44% Sol. 2.3 mole Water enough to make up 45% N.V.
Sodium hydroxide 50% Sol. .17 mole - 10 _ , ' . ' . ~
~07~044 Cresol, phenol, propylene glycol, formaldehyde 90% of requirement and water was loaded heated at 40 with 2/3 of the sodium hydroxide require-ment. The mixture was held at 60C for 30 minutes. The remainder of form-aldehyde and sodium hydroxide was added and the mixture held at 85 for viscosity F. The resin was cooled down for storage.
Example 18. RESIN GS
The above resin was spray dried (215-105) to give a product with cure of 15 sec.
Example 19. WAFERBOARD FROM RESIN GS
Waferboard (5/16") prepared from the G S resin at press temperature of 410F, 400 psi and 4 minute press cycle had IB of 44.2, MOR 2420.
Example 20. RESIN E S
Resin E L was prepared following the procedure described under Resin DL, and was treated with ethylene glycol (12% approx. on phenol taken initially) and spray dried into free flowing powder with flow and cure (15-30 sec.) possessing solubility in water.
Example 21. WAFERBOARD FROM RESIN E S
Preparation and Results: 7/16" Boards prepared with 3% resin (powder) at 400F and 3.5 minutes press had IB 28.5 and MOR of 2420.
Example 22. RESIN F L
Phenol 1 mole ; Formaldehyde (44% Sol.) 2.0 mole Calcium Hydroxide 1% on phenol Sodium Hydroxide (50% Sol.) .32 mole -Water To make up 45% N.V.
The resin was prepared by heating phenol, formaldehyde (85% of requirement), water and calcium hydroxide (1/5 of requirement) at 50C for 30 minutes and then adding the remainder of the catalyst in two portions and holding the mixture at 60C and 80C respectively for 30 minutes after each addition. Balance of formaldehyde and sodium hydroxide were added and the - 11 _ .. .. . .:
- ~ , ' ~ . ' - . ~ ' .: . .
mixture held at 80C for viscosity D. The resin was cooled rapidly for stor-age.
Example 23. RESIN FS
The above resin was treated with butylene glycol (6% approx. on phenol taken initially) and spray dried to a free flowirlg powder, with flow and cure (25-35 sec.) and solubility in water.
Example 24. WAFERBOARD FROM RESIN FS
Board prepared using the resin (3% powder) at 400F and 3 1/2 minutes press had IB 95.5 and ~OR 2908.
., :
,
This lack of stability severely limits product usefulness, as dilutability and viscosity are adversely affected by storage. As a consequence, these aqueous systems have to be prepared close to where they are to be used, and ideally are prepared and used at the same rate, with minimal storage times.
Also, where some transportation cannot be avoided, since the system contains of the order of 50% water, transportation is costly, particularly in compari-son with the known solid resins. Further, the high water content of liquid resins is undesirable in applications where prolonged heat application to effect its removal is required. In addition to the cost, such prolonged heating can adversely affect the material being bonded, with detriment to the properties of the product.
We have now found that a range of phenol-aldehyde resins, hitherto known only as aqueous solutions or dispersions, can be obtained as a parti-culate solid by spray-drying such an aqueous suspension or solution. We have further found that the capability of such resin solutions or dispersions being processable to a particulate solid by spray drying is markedly enhanced by the incorporation therein of a non-phenolic polyhydroxy compound.
Thus in one embodiment this invention provides a method of preparing a phenol-formaldehyde resin in solid particulate form comprising reacting together, in an aqueous medium, phenol and formaldehyde, in a ratio of 1.0 mole phenol to between 1.8 and 3.5 moles of formaldehyde, in the presence of between 0.1 and 1.0 mole of a basic catalyst; continuing this reaction until a desired viscosity is reached; spray drying the solution or dispersion of -1- ~ ., phenol-formaldehyde resin thus produced in a pressure nozzle drier; and chilling the spray dried particulate solid so produced for storage.
In a preferred embodiment this invention provides a method of pre-paring a phenol-formaldehyde resin in solid particulate form comprising reac-ting together, in an aqueous medium, phenol and formaldehyde, in a ratio of 1.0 mole of phenol to between 1.8 and 3.5 moles of formaldehyde in the pre-sence of between 0.1 and 1.0 moles of a basic catalyst; continuing this reaction until a desired viscosity is reached; modifying the reaction system by adding thereto between 0 and 30%, based on the weight of the phenol origin-ally taken, of a non-phenolic polyhydroxy compound; spray drying the thus modified liquid resin in a pressure nozzle drier; and chilling the spray dried particulate solid for storage.
In an alternative process according to this embodiment of the inven-tion, the non-phenolic polyhydroxy compound is incorporated at up to 30% by weight of phenol into the initial reaction mixture.
Insofar as the conditions of reaction, and reactants used in pre-paring the phenol-formaldehyde resin are concerned, standard conditions, proce-dures, and reactants well known in the art are used.
The term "phenol" can include not only pure and technical grade phenol, but also cresols with a high meta- and para-cresol content. The preferred phenol composition is one with a boiling range of 180 -200C, con-taining not more than 15% by weight of ortho-cresol plus xylenols.
The formaldehyde, can be used in any of the commercially available forms containing from 37% to 100% aldehyde, such as aqueous solutions, para-formaldehyde, etc. An aqueous solution of formaldehyde is preferred.
The basic catalyst can be an alkali hydroxide, or carbonate, or an alkaline earth oxide or hydroxide. The preferred catalyst is sodium hydroxide, but barium hydroxide, calcium hydroxide and calcium oxide all produce usable resins.
~074044 The non-phenolic polyhydroxy compound can be chosen from glycols, such as ethylene glycol, propylene glycol, butylene glycol, and diethylene glycol; polyhydroxy ethers, such as the Voranols*, and other polymeric hydroxy materials, for example the Carbowaxes*; and polyhydroxy compounds such as glycerol, sorbitol, cane sugar, etc. It is also contemplated that mixtures of polyhydroxy compounds can also be used.
To obtain a useful adhesive resin suitable for spray drying, the molar ratios of phenol, formaldehyde, and catalyst have to be controlled and kept within the following limits: phenol, 1.0 mole; formaldehyde, 1.8 to 3.5 moles; catalyst, 0.1 to 1.0 moles. The amount of polyhydroxy compound also should not exceed 30% by weight of the weight of phenol taken.
In an alternative embodiment, this invention provides a spray-dried particulate solid phenol-formaldehyde resin, containing up to 30% by weight of the phenol present of a polyhydroxy compound.
Preferably the spray drying step is carried out on the liquid resin dissolved or dispersed in water using a pressure nozzle drier. It is desir-able to chill the spray dried particles quickly to below 20C for storage.
The nature of the product can be further modified for use by the introduction of other materials, such as dyes; extenders and fillers; plasti-cisers; anti-static agents; release agents; and so forth.
The spray dried phenolic adhesives of this invention have a number of advantages, especially where systems which it has not hitherto been poss-ible to convert into solid form are concerned. The spray dried material is an easily handled, free flowing powder, which can be used as such, or, where relevant reconstituted to a liquid system by the addition of the desired amount of water. Particular advantages obtained by use of these solids are:
(a) the solid systems do not suffer from the lack of stabili~y exhibited by liquid systems; they can be stored if kept dry and preferably below about 70 to 75F (21 to 24C) for at least 6 months, as compared to their liquid i * Trade Mark counterparts which have only a limited shelf-life.
(b) wllere relevant, reconstitution to a liquid resin with retention of desirable viscosity and dilutability characteristics.
~c) shorter pressing times and lower pressing temperatures when spray-dried adhesive is used in place of liquid adhesive in manufacture of waferboard, chipboard and the like, thus maintaining short cure cycles and minimising damage to the furnish.
~d) better economics of storage and transportation as the 50% water content of a liquid resin is removed.
~e) better utilization of resin, since the loss of relatively low molecular weight components, which generally are lost in, for example, the white water in board making, is virtually eliminated; this has the consequence that pollution problems associated with white water treatmen* are also alleviated.
~f) improved economics of production involving shorter batch processing -times, and powder production without grinding.
Spray drying is an operation in which a liquid feed is converted to a fine spray, the moisture in the feed evaporated by means of a stream of hot gas (usually air) and the dry powdered product then separated from the gas. The process can be applied to solutions, emulsions or slurries or any material that can be pumped. Moisture evaporation, both free and chemically bound, is controlled by temperature and moisture gradients in the material during drying. The ease of drying of materials depends on the temperature difference between inlet and outlet drying air - the greater permissible difference, the easier the drying.
Spray dried particles are usually spherical; solutions produce hollow beads while slurries produce solid beads. The particle size varies with degree of atomization and percent solids in the feed. Other character-istics of the dried material such as moisture content, flowability, etc. are controlled by operational variables such as droplet size, air flow rate, air temperature and humidity.
Phenol-formaldehyde resins fall into a class of materials that have low softening points. During drying, the tacky particles have to be chilled down below softening point in the layer of cool air and thus be pre-vented from sticking to surfaces. Generally used temperatures for drying phenol-formaldehyde resins are 210 - 180C at the inlet and 90 - 100C at the outlet.
In the Examples, the following test procedures are used to obtain the cited test results.
A. MELT POINT, FLOW AND CURE OF REACTIVE PHENOLICS
Softening Point - Capillary Method A capillary sealed at one end is filled with powdered material to a depth of 2 cm. The tube is attached to a thermometer so that the resin is next to the bulb and the thermometer is immersed in a clear bath heated at 3C/min. The softening point is recorded as the point at which the resin first contracts away from the side of the capillary tube.
Inclined Glass Plate Flow Test A pressed pellet of the resin (0.5 g) is placed at one end of glass plate kept in horizontal position at 125C in convection oven. After 3 min.
preheat time, the plate is tilted 65 from horizontal and testing continued for additional 20 minutes. The glass plate is removed from the oven, cooled and the length of the flow is measured in millimeters and recorded.
Hot Plate Cure Powdered resin (lg) is spread over 2" square area on a hot plate maintained at 150C. Timing is started and the resin is stroked and patted alternately. As the resin advances and becomes more viscous, it will 'string' from spatula during patting. The point in time at which the resin no longer sticks to the spatula and the spatula lifts clear is recorded as the cure time.
1~74~D44 _. MODULUS OF RUPTURE (ASTM D1037) Modulus of rupture (MOR), a static bending test, is carried out us-ing a suitable testing machine (E4) on preconditioned or soaked specimens cut along the two dimensions of the board and measuring 3" x 6" for boards over 1/4" thick. The specimens are subjected to load application at mid span with supports being 4" apart at a uniform rate of load increase.
Modulus of rupture is reported in pounds per square inch calculated from 3 x maximum load x span MOR 2 x width of spec. x (thickness)2 C. INTERNAL BOND (ASTM D1037) Internal bond strength (IB) or tensile strength perpendicular to the surface is determined by testing preconditioned 2" x 2" specimens.
The specimens are bonded to the loading blocks which are engaged in heads of the testing machine. The specimens are subjected to stress to failure with the load passing through the center of the specimens in a continuous fashion at a uniform rate.
Internal bond strength is calculated from the maximum load at fail-ure per square inch. The location of the line of failure is also reportèd.
D. VISCOSITY
Viscosity measured by means of a Gardner-Hold Viscosity Comparator, to stated letter viscosity.
Examples Example 1. RESIN A L
Phenol 1 mole Pormaldehyde (44% Sol.) 2 moles Sodium Hydroxide (50% Sol.) .65 mole Water To make up 45% N.V.
Phenol, formaldehyde, water and 1/3 amount of base required were heated under reflux with agitation to 60 and held at 60C with cooling for .. . . - . - :~
: . ' : -, ' : ,, -, : . ' ~ :, . .
30 minutes. The balance of sodium hydroxide was added and the mixture held at 80C to viscosity D. The resin was cooled rapidly for storage.
Example 2. RESIN A S
The above liquid resin was spray dried at 45~ solids to give a free flowing powder with no flow or cure but infinite solubility in water.
Example 3. HARDBOARD FROM RESINS AL, AS
Resin A S was reconstituted with water to 45% solids and then dilu-ted further to 8% solids. The dilute resin solution was sprayed into a wood furnish slurry buffered at pH 4.5 at 2% resin level. The slurry was drained and the mat pressed at 350F for 6 min. to form hardboard.
Hardboard was also prepared with original liquid resin AL.
Physical testing: AL IB 34 psi AS IB 38 psi Example 4. RESIN B L
Phenol l mole Formaldehyde ~37% Sol.) 2 mole Sodium Hydroxide ~50% Sol.) 0.83 mole l~ater to make up 45% N.V.
Phenol, formaldehyde ~l/2 of requirement) water and sodium hydroxide ~56% of requirement) were heated under reflux with agitation to 100C and held at the temperature until viscosity T was reached. The mixture was cooled to 60C and formaldehyde (balance) was added and the mixture held at 75 until viscosity X was reached. The mixture was cooled to 50C and the balance of sodium hydroxide was added and the resin held at 60C for viscosity 0. The resin was cooled rapidly for storage.
Example 5. RESIN B S
The above liquid resin was spray dried at 45% solids to a free flowing powder with no flow or cure but fully soluble in water.
.. .
1074044 :
Example 6. PLYWOOD FROM RESIN B S
Resin B S was reconstituted with water to 45% solids and formulated into plywood adhesive using the following formulation:
Resin200 parts Water60 parts Norprofil 30 parts Wheat flour 6 parts Soda Ash 6 parts Exterior grade plywood was prepared using the above mix as adhesive at 58 lb/1000 sq. ft. double glueline at 300F, 200 psi for 3/8" thick, 3 ply, at 4.75 mins. press time for two panels per opening. This was compared with the product obtained with original liquid resin as adhesive. The speed of cure was compared for BL and BS resins, using wood failure test as specified by ASTM.
Press time, min.
4.75 5.25 6.25 BL Wood Failure %49 68 74 BS Wood Failure %23 64 98 Example 7. RESIN C L
Phenol 1 mole Propylene Glycol 0.5 mole Formaldehyde ~44% Sol.) 1.9 mole Sodium Hydroxide ~50% Sol.) 0.18 mole Water To make up 45% N.V.
Phenol, propylene glycol, water, formaldehyde ~90% of requirement) and sodium hydroxide ~50% of requirement) was held with agitation at 50C
for 30 minutes. Formaldehyde ~balance of requirement) and sodium hydroxide ~25% of requirement) was added and the mixture heated to 75C and held at that temperature for 30 minutes. Balance of sodium hydroxide was added and the reaction mixture held at 75C for viscosity H. Resin was cooled rapidly for storage.
'' , ,,:, ' : '. . ' -- , . ~ , . . . .
' ' ' ' '~
1~74044 Example ~. RESIN C S 1 The resin C L was spray dried to a find powder which had limited solubility in water and cure of 0-10 sec.
Example 9. RESIN C S 2 The resin CL was treated with propylene glycol (6% approx. on phenol used initially) and spray dried, to a fine powder with cure of 10-30 sec and solubility in water.
Example 10. WAFERBOARD FROM RESIN C S 2 Preparation and Results: 7/16~' Board prepared at 3% resin content.
pressed at 410 F for 4 minutes had IB 44.5 and MOR 3360.
Moulding compound from C S 2 A moulding compound was prepared using the above resin by processing the following mix:
Resin 100 parts Line 2 parts Carbon Black4 parts Calcium Stearate1 part Wood flour106 parts Asbestos 4 parts Furfural 1.5 parts A compound with 50 sec. cure and 8 sec. flow at 150 psi was ; obtained.
Example 11. RESIN D L
Phenol 1 mole Formaldehyde (44% Sol.) 2.2 mole Barium Hydroxide4% on phenol Sodium Hydroxide t50% Sol.) .7 mole Water To make up 45% N.V.
Phenol, formaldehyde, water and barium hydroxide (1/5 of the requirement) were heated to 50 with agitation and held at that temperature _ 9 _ , 107~044 for 30 minutes. More barium hydroxide (2/5 of requirement) was added and the mixture held at 60C for 30 minutes. The balance of barium hydroxide was then added and the mixture held at 80C for 30 minutes. Sodium hydroxide was next added in two portions and the resin held at 90 for viscosity G.
The resin was cooled rapidly for storage.
Example 12. RESIN D S
The above liquid resin was spray dried into a fine powder, possess-ing flow and cure (0-10 sec.) and infinite solubility in water.
Example 13. WAFERBOARD FROM RESIN D S
Preparation and results: 7/16" Boards prepared with 3% solid resin at 400F
for 5 minutes had IB 45.0 and MOR 2615.
Example 14. RESIN E L
Phenol 1 mole Formaldehyde (44% Sol.) 2.2 mole Calcium Oxide 5%
Sodium Hydroxide ~50% Sol.) .42 mole Water to make up 45% N.V.
Example 15. RESIN FS
The above resin was treated with propylene glycol (8% approx. on phenol taken initially) and spray dried to a free flowing powder with flow and cure (25-35 sec.) possessing solubility in water.
Example 16. WAFERBOARD FROM RESIN FS
5/16" Board prepared with the resin (3% powder) at 400F and 4 minutes press had IB 55.5 and MOR 2682.
Ex~mple 17. RESIN G L
Cresol .15 mole Phenol 1.0 mole Propylene Glycol.3 mole Formaldehyde 44% Sol. 2.3 mole Water enough to make up 45% N.V.
Sodium hydroxide 50% Sol. .17 mole - 10 _ , ' . ' . ~
~07~044 Cresol, phenol, propylene glycol, formaldehyde 90% of requirement and water was loaded heated at 40 with 2/3 of the sodium hydroxide require-ment. The mixture was held at 60C for 30 minutes. The remainder of form-aldehyde and sodium hydroxide was added and the mixture held at 85 for viscosity F. The resin was cooled down for storage.
Example 18. RESIN GS
The above resin was spray dried (215-105) to give a product with cure of 15 sec.
Example 19. WAFERBOARD FROM RESIN GS
Waferboard (5/16") prepared from the G S resin at press temperature of 410F, 400 psi and 4 minute press cycle had IB of 44.2, MOR 2420.
Example 20. RESIN E S
Resin E L was prepared following the procedure described under Resin DL, and was treated with ethylene glycol (12% approx. on phenol taken initially) and spray dried into free flowing powder with flow and cure (15-30 sec.) possessing solubility in water.
Example 21. WAFERBOARD FROM RESIN E S
Preparation and Results: 7/16" Boards prepared with 3% resin (powder) at 400F and 3.5 minutes press had IB 28.5 and MOR of 2420.
Example 22. RESIN F L
Phenol 1 mole ; Formaldehyde (44% Sol.) 2.0 mole Calcium Hydroxide 1% on phenol Sodium Hydroxide (50% Sol.) .32 mole -Water To make up 45% N.V.
The resin was prepared by heating phenol, formaldehyde (85% of requirement), water and calcium hydroxide (1/5 of requirement) at 50C for 30 minutes and then adding the remainder of the catalyst in two portions and holding the mixture at 60C and 80C respectively for 30 minutes after each addition. Balance of formaldehyde and sodium hydroxide were added and the - 11 _ .. .. . .:
- ~ , ' ~ . ' - . ~ ' .: . .
mixture held at 80C for viscosity D. The resin was cooled rapidly for stor-age.
Example 23. RESIN FS
The above resin was treated with butylene glycol (6% approx. on phenol taken initially) and spray dried to a free flowirlg powder, with flow and cure (25-35 sec.) and solubility in water.
Example 24. WAFERBOARD FROM RESIN FS
Board prepared using the resin (3% powder) at 400F and 3 1/2 minutes press had IB 95.5 and ~OR 2908.
., :
,
Claims (16)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:-
1. A method of preparing a phenol-formaldehyde resin in particulate form comprising reacting together, in an aqueous medium, phenol and formalde-hyde, in a ratio of 1.0 mole phenol to between 1.8 and 3.5 moles of formalde-hyde; in the presence of between 0.1 and 1.0 mole of a basic catalyst; con-tinuing this reaction until a desired viscosity is reached; spray-drying the solution or dispersion of phenol-formaldehyde thus produced in a pressure nozzle drier; and chilling the spray dried particulate solid for storage.
2. A method of preparing a modified phenol-formaldehyde resin in solid particulate form comprising reacting together, in an aqueous medium, phenol and formaldehyde, in a ratio of 1.0 mole phenol to between 1.8 and 3.5 moles of formaldehyde, in the presence of between 0.1 and 1.0 moles of a basic catalyst; continuing this reaction until a desired viscosity is reached;
modifying the reaction system by adding thereto between 0% and 30%, based on the weight of phenol originally taken of a non-phenolic polyhydroxy compound;
spray drying the thus modified liquid resin in a pressure nozzle drier, and chilling the spray dried particulate solid.
modifying the reaction system by adding thereto between 0% and 30%, based on the weight of phenol originally taken of a non-phenolic polyhydroxy compound;
spray drying the thus modified liquid resin in a pressure nozzle drier, and chilling the spray dried particulate solid.
3. Process according to claim 2, wherein the polyhydroxy compound is added to the reaction system after the desired viscosity is reached and before spray drying thereof.
4. Process according to claim 2 wherein the polyhydroxy compound is incorporated into the initial reaction mixture.
5. Process according to claims 1 or 2 wherein pure or technical grade phenol is used.
6. Process according to claims 1 or 2 wherein the phenol is replaced at least in part by a cresol mixture having a high meta- and para-cresol content.
7. Process according to claim 1 or 2 wherein a technical grade phenol is used, having a boiling range of 180° to 200°C and containing not more than 15% by weight of ortho-cresol plus xylenols.
8. Process according to claim l or 2 wherein an aqueous solution of formaldehyde is used.
9. Process according to claim 2, 3, or 4 wherein the polyhydroxy compound is chosen from glycols, polyhydroxy ethers, polyhydric alcohols, sugars, and polymeric hydroxyl group containing substances.
10. Process according to claim 2, 3, or 4 wherein the polyhydroxy compound is chosen from ethylene glycol, propylene glycol, and butylene glycol.
11. A spray dried particulate solid phenol-formaldehyde resin containing up to 30% by weight of the phenol used in its preparation of a polyhydroxy compound.
12. Phenol-formaldehyde resin according to claim 11 prepared from pure or technical grade phenol.
13. Phenol-formaldehyde resin according to claim 11 in which at least part of the phenol is replaced in preparation by a cresol mixture having a high meta- and para-cresol content.
14. Phenol-formaldehyde resin according to claim 11 prepared from a technical grade phenol, having a boiling range of 180°C to 200°C, and con-taining not more than 15% by weight of ortho cresol plus xylenols.
15. Phenol-formaldehyde resin according to claim 11 in which the polyhydroxy compound is chosen from glycols, polyhydroxyethers, polyhydric alcohols, sugars, and polymeric hydroxyl group containing substances.
16. Phenol-formaldehyde resin according to claim 11 in which the poly-hydroxy compound is chosen from ethylene glycol, propylene glycol, and butylene glycol.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB39958/75A GB1545506A (en) | 1975-09-30 | 1975-09-30 | Spray-dried phenolic resins |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1074044A true CA1074044A (en) | 1980-03-18 |
Family
ID=10412426
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA259,975A Expired CA1074044A (en) | 1975-09-30 | 1976-08-27 | Spray-dried phenolic adhesives |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4098770A (en) |
| AT (1) | AT366396B (en) |
| CA (1) | CA1074044A (en) |
| GB (1) | GB1545506A (en) |
| ZA (1) | ZA765275B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7064175B2 (en) | 2002-04-26 | 2006-06-20 | Mitanic, Inc. | Adhesive system containing tannin for binding lignocellulosic materials |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1138589A (en) * | 1979-04-20 | 1982-12-28 | Krishan K. Sudan | Lignosulphonate phenolic resin binder |
| US4269949A (en) * | 1979-06-27 | 1981-05-26 | Borden, Inc. | Phenol formaldehyde resin for hardboard applications |
| US4316827A (en) * | 1980-04-17 | 1982-02-23 | Union Carbide Corporation | Rubber modified phenolic friction particles |
| US4433120A (en) * | 1981-09-30 | 1984-02-21 | The Borden Chemical Company (Canada) Limited | Liquid phenolic resin composition and method for waferboard manufacture |
| CA1166392A (en) | 1981-12-07 | 1984-04-24 | Otto G. Udvardy | Thermoplastic fast-curing powdered resol and novolac resin mixtures |
| JPS5980437A (en) * | 1982-10-28 | 1984-05-09 | Kanegafuchi Chem Ind Co Ltd | Method for forming condensate of aldehydic compound with phenolic compound into fine particle |
| US4708967A (en) * | 1986-03-25 | 1987-11-24 | Reheis Chemical Company, Inc. | Thermosetting resin binder particles and methods for making waferboard |
| US5047275A (en) * | 1989-07-26 | 1991-09-10 | Borden, Inc. | Spray dried phenol-formaldehyde resin compositions |
| US5019618A (en) * | 1989-07-26 | 1991-05-28 | Borden, Inc. | Spray dried phenol-formaldehyde resin compositions |
| CA2152345A1 (en) * | 1993-11-16 | 1995-05-26 | Charles R. Davis | Preparation of wood laminates |
| US5501720A (en) * | 1994-06-13 | 1996-03-26 | Georgia-Pacific Corporation | Spray-dried urea-formaldehyde and lignosulfonate compositions |
| US6113729A (en) * | 1998-08-10 | 2000-09-05 | Borden Chemical, Inc. | Wax sizing and resin bonding of a lignocellulosic composite |
| FI990674A (en) | 1999-03-26 | 2000-09-27 | Neste Chemicals Oy | Process for the preparation of polymers |
| WO2000058400A1 (en) * | 1999-03-26 | 2000-10-05 | Dynea Chemicals Oy | Method for the preparation of polymers |
| US6818707B2 (en) * | 2002-01-08 | 2004-11-16 | Borden Chemical, Inc. | Spray dried phenolic resole molding powder with crystalline phenolic compounds |
| US6608162B1 (en) | 2002-03-15 | 2003-08-19 | Borden Chemical, Inc. | Spray-dried phenol formaldehyde resins |
| US20040186218A1 (en) * | 2003-03-18 | 2004-09-23 | Borden Chemical, Inc. | Novel tunable hybrid adhesive system for wood bonding applications |
| CN101702889B (en) * | 2007-01-22 | 2013-07-24 | 莫比乌斯科技有限公司 | Composite panel with solid polyurethane binder, and process for manufacture |
| US8569430B2 (en) | 2009-12-09 | 2013-10-29 | Georgia-Pacific Chemicals Llc | Method of spray drying phenol-formaldehyde resin |
| US9169385B2 (en) * | 2011-09-30 | 2015-10-27 | Georgia-Pacific Chemicals Llc | Powdered resins with fillers |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1660403A (en) * | 1924-02-20 | 1928-02-28 | Bakelite Corp | Process for the continuous preparation of phenolic resins |
| US2315432A (en) * | 1940-04-26 | 1943-03-30 | American Cyanamid Co | Casting of phenolic resins |
| US2376213A (en) * | 1941-12-17 | 1945-05-15 | Ford Motor Co | Phenol-formaldehyde resin |
| US2976574A (en) * | 1956-07-31 | 1961-03-28 | Union Carbide Corp | Chemical process and product |
| US3661814A (en) * | 1970-12-21 | 1972-05-09 | Dow Chemical Co | Phenol-formaldehyde adhesive resins by addition of polyhydric alcohols |
-
1975
- 1975-09-30 GB GB39958/75A patent/GB1545506A/en not_active Expired
-
1976
- 1976-08-27 CA CA259,975A patent/CA1074044A/en not_active Expired
- 1976-09-02 ZA ZA765275A patent/ZA765275B/en unknown
- 1976-09-15 US US05/723,250 patent/US4098770A/en not_active Expired - Lifetime
- 1976-09-30 AT AT0723876A patent/AT366396B/en not_active IP Right Cessation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7064175B2 (en) | 2002-04-26 | 2006-06-20 | Mitanic, Inc. | Adhesive system containing tannin for binding lignocellulosic materials |
Also Published As
| Publication number | Publication date |
|---|---|
| AT366396B (en) | 1982-04-13 |
| GB1545506A (en) | 1979-05-10 |
| ZA765275B (en) | 1977-08-31 |
| ATA723876A (en) | 1981-08-15 |
| US4098770A (en) | 1978-07-04 |
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